8 ms·

Headphone inline controls – how they differ on Apple iOS vs. Android/Nokia

170 points by sengork 10y ago

jswny 10y ago
Wow I had no idea this is why Apple headphones don't work on other devices. I was under the impression they did not work because apple devices are 3 pole vs. everything else being 2 pole.
- davidbanham 10y ago
  Everything with a microphone is 3 pole.
  - brians 10y ago
    Everything discussed in the article is 4-pole, isn't it? L, R, G, Mic? These days, Apple devices are 8-pin 2-lane lightning, and use separate lanes for audio and control. The Apple EarPods appear to be 7-pole: separate grounds for each signal wire, all as twisted pair. That's pretty cool, as someone who wants earbuds to work well near RFI.
    - Godel_unicode 10y ago
      > ...wants earbuds to work well near RFI. This is the first time I've heard that argument, what RFI are you near that was breaking normal headphones?
      - kuschku 10y ago
        > what RFI are you near that was breaking normal headphones? Mobile phones. The good old br t br t brrr tt br whenever the mobile phone thinks it has low signal and fires at full power and causes interference. A video demonstrating it: https://www.youtube.com/watch?v=8TWXCVbBTcc https://www.youtube.com/watch?v=8TWXCVbBTcc
        tjohns 10y ago
        That sound has less to do with power level, and more to do with what mode your phone's modem is using. Specifically, that sound is associated with TDMA-style networks (e.g. 2G GSM), since the transmitter has to rapidly switch on/off, giving other phones a chance to transmit. This induces a series of audible-frequency voltage spikes in nearby cables. CDMA-style networks (e.g. CdmaOne, 3G GSM, LTE) don't have that problem, since the transmitter is effectively always on while transmitting. That's why you don't notice that sound very often anymore.
        yaantc 10y ago
        LTE uses OFDMA, which has nothing to do with CDMA (no superposition and coding separation). OFDMA is a combination of frequency and time division: time wise, the allocation unit is a subframe of 1 ms (to be compared with a 2G GSM burst duration of 0.577 ms, so not that far) and frequency wise a subframe is made of "resource blocks" (RBs) of 12 subcarriers of 15 kHz each (so 1 RB = 180 kHz total). What's allocated to a device is a set of RB in a subframe, and this is repeated as needed accross subframes in time. 3G used a 10 ms allocation unit, but with HSPA it's been reduced to 2 ms to become more "TDM-like" (it turns out that in real life code superposition is not so good, better split in time and do less superposition: less interference, less power consumption, better results). I honestly don't know the source of the 2G noise, but from the above it's not as simple as TDM vs. no TDM, as current 3G and LTE both in practice have a time-based allocation component on roughly similar granularity as 2G. One difference could be the transmission power: 2G can go up to 2W, while LTE is 200 mW maximum so 10 times less. I don't have 3G peak Tx power in mind, but in practice I guess it should be closer to LTE than 2G (interference minimization in a same frequency / reuse 1 network: both LTE and CDMA are reuse 1 deployment, while 2G is not). That will certainly cause a 2G device to have higher power spikes. And I guess the details of the transmit pattern are likely to play a role too.
        kuschku 10y ago
        > That's why you don't notice that sound very often anymore. Except yesterday. And today. And every second day in my life. Because even my Nexus 5X in a 4G network occasionally sends/receives SMS in GSM mode.
    - PascLeRasc 10y ago
      Ground is an "implied pole" as you'd need it for anything, it's just 3 different upstream channels (L,R,mic) feeding into it.
  - eon1 10y ago
    While in practice that may be mostly true, it's not necessarily a fact. Unbalanced microphones can and do exist.
    - quesera 10y ago
      I think GP was referring to the conductors on a standard stereo+mic 3.5mm plug, which of course really has four conductors, but three prominent dividing marks. These are unbalanced mics. I've never seen balanced mics outside of recording studios.
- jrockway 10y ago
  Apple headphones work with other devices. I use the iPhone headphones for videoconferences on my Asus Chromebox, for example.
joecool1029 10y ago
Pretty sure Blackberry use the Apple 'standard' as well.
wlesieutre 10y ago
To be more precise than "they don't work because Apple is terrible," the two competing pinout standards are CTIA (previously meaning Cellular Telephone Industries Association) and OMTP (Open Mobile Terminal Platform). According to Wikipedia, the OMTP devices include: * old Nokia (and also Lumia starting from the 2nd gen) * old Samsung (2012 Chromebooks) * old Sony Ericsson (2010 and 2011 Xperias) * Sony (PlayStation Vita) * OnePlus One * Xbox One controller with head phone jack * iPhone sold in China and CTIA devices include: * Apple * HTC * LG * Blackberry * latest Nokia (including 1st gen Lumia as well as later models) * latest Samsung * Jolla * Sony (Dualshock 4) * Microsoft (including Surface and Xbox One controller with chat adapter) * most Android phones https://en.wikipedia.org/wiki/Phone_connector_(audio)#TRRS_standards https://en.wikipedia.org/wiki/Phone_connector_(audio)#TRRS_s... I haven't personally tested most of those, but IIRC when I had a Surface Pro the iPhone TRRS earbuds worked fine with it.
- stonogo 10y ago
  CTIA is a post-facto 'standardization' of what used to be known as 'AHJ,' which came about once companies needed a name for 'Apple-compatible' without actually naming Apple. CTIA is primarily a lobbying organization, and their past hits include laws that made it easier for the US government to surveil email and an attempt to get the US government to shut off TV broadcasting entirely. OMTP was an actual standard from a real-life standards body -- the same one that brought us micro-USB across all non-Apple phones. We lost functionality when we lost OMTP; imagine a world where you had dedicated buttons for track forward and back. Having been involved in the design phase of devices that supported each standard, I miss OMTP.
  - comex 10y ago
    > We lost functionality when we lost OMTP; imagine a world where you had dedicated buttons for track forward and back. There's one argument, albeit small, for killing the headphone jack. USB HID has included track control keycodes since forever, so USB earphones should be able to control playback by appearing as a HID device... I think... Of course, there too Apple is off doing their own thing with Lightning.
jws 10y ago
For the curious or confused by the "when you tap the button it shoots an electrical signal that the phone will pick up and interpret" in the article, the control buttons are implemented as resistors switched across the mic/ground pair. The mic is 1000Ω or higher. The functions resistors are lower. You can see nice diagrams at… http://source.android.com/devices/accessories/headset/plug-headset-spec.html http://source.android.com/devices/accessories/headset/plug-h...
- hugodahl 10y ago
  Very nice and handy reference! Will give me something to compare against and my Pixel and Amazon headset. Apparently, vol up on the headset triggers the assistant, while all other buttons work as expected. Oddly, the same headset worked flawlessly on a OPO and Nexus 6. And Google hardware support cannot recommend a specific make/model, just one with "an on/off switch for the mic".
tooFastFuckYou 10y ago
The best is when Apple's shitty headphone jack goes bad, the connection gets flaky, and it starts sending spurious "commands" to the phone. And why is Apple's headphone jack shitty? The conspiracy theorist would say that Apple wanted to justify their idiotic decision to eliminate it. The realist would say it's because of Apple's idiotic mania to make everything "thinner," which is used as an excuse to compromise everything from battery life to the quality of internal components on all of its products.
simonjgreen 10y ago
This is not a fair representation of the situation at all, and also doesn't even hold true. For example, I recently switched from iPhone to Galaxy S7. My apple earbuds centre button pauses and resumes but the volume controls do nothing. So the problem is not as straightforward as Apple vs Android.
rickdeckard 10y ago
Apple didn't patent a "resistance", they implemented a control-chip in their headphones starting from the iPod Shuffle in ~2009, and patented that chip. Purpose was to ensure a revenue-share from headphones so that every accessory-maker who wanted in-line controls had to pay a license to Apple to use the control-chip. (the control-chip was meanwhile reverse-engineered and its functionality is now integrated in non-licensed headphones as well)
- bostand 10y ago
  "ensure a revenue-share" Such a nice word for such an ugly business practice....
tener 10y ago
> In other words- you could have a device with the same TRRS Pinout as apple products- but the headset wont work because the resistances (ohms) of the headphones send signals that your phone is not allowed to interpret into the correct actions (since apple patented these) Can you seriously patent actual resistances?
mattkevan 10y ago
Has this got anything to do with the way inline controls seem to be unreliable in Android? I got out of the habit of using them as there was only a 50/50 chance of anything happening when pressing a button. Sometimes even when successful it would take a while to take effect. Pressing the button a few times in case it didn't register led to nonsense like it stopping and starting rapidly a few seconds later. I first noticed this on a Fairphone on 4.2 and just thought it was due to a sluggish phone on an old system, but the problem remained on a Nexus 6 with versions 5 and 6. Also Android seems to be bad at remembering the last audio app that was open. On iOS, you can listen to something, unplug the headphones, do something, plug them back in, hit the play button and you carry on where you left off. Android not so much - you have to manually open the app for it to work. Although I once had a podcast app and a music app start at the same time.
- aembleton 10y ago
  I find Poweramp [1] reliably starts every time I plugin my earphones. 1. http://powerampapp.com/ http://powerampapp.com/
- hsod 10y ago
  > On iOS, you can listen to something, unplug the headphones, do something, plug them back in, hit the play button and you carry on where you left off In my experience, this doesn't work very well anymore on iOS 10
codfrantic 10y ago
To make things even more complicated, I have a Sony Xperia Z2 which uses a 5 point jack plug TRRRS, as far as I know the extra connection is only used to receive microphone signal from the included noise cancelling headphones.[1] (Since the noise cancelling logic is handled on the phone). [1] https://www.sonymobile.com/global-en/products/accessories/digital-noise-cancelling-headset-mdr-nc31em/ https://www.sonymobile.com/global-en/products/accessories/di...
nickcano 10y ago
This causes a ton of compatibility problems, and it's worse that a lot of companies don't seem to care and advertise compatibility anyways. I noticed this a while ago when I wrote this review: https://www.amazon.com/review/R2RH78QWKSM5W7/ref=cm_aya_cmt?ie=UTF8&ASIN=B004SP0WAQ https://www.amazon.com/review/R2RH78QWKSM5W7/ref=cm_aya_cmt?...

170 points by sengork 10y ago

jswny 10y ago

Wow I had no idea this is why Apple headphones don't work on other devices. I was under the impression they did not work because apple devices are 3 pole vs. everything else being 2 pole.

davidbanham 10y ago
Everything with a microphone is 3 pole.
- brians 10y ago
  Everything discussed in the article is 4-pole, isn't it? L, R, G, Mic? These days, Apple devices are 8-pin 2-lane lightning, and use separate lanes for audio and control. The Apple EarPods appear to be 7-pole: separate grounds for each signal wire, all as twisted pair. That's pretty cool, as someone who wants earbuds to work well near RFI.
  - Godel_unicode 10y ago
    > ...wants earbuds to work well near RFI. This is the first time I've heard that argument, what RFI are you near that was breaking normal headphones?
    - kuschku 10y ago
      > what RFI are you near that was breaking normal headphones? Mobile phones. The good old br t br t brrr tt br whenever the mobile phone thinks it has low signal and fires at full power and causes interference. A video demonstrating it: https://www.youtube.com/watch?v=8TWXCVbBTcc https://www.youtube.com/watch?v=8TWXCVbBTcc
      - tjohns 10y ago
        That sound has less to do with power level, and more to do with what mode your phone's modem is using. Specifically, that sound is associated with TDMA-style networks (e.g. 2G GSM), since the transmitter has to rapidly switch on/off, giving other phones a chance to transmit. This induces a series of audible-frequency voltage spikes in nearby cables. CDMA-style networks (e.g. CdmaOne, 3G GSM, LTE) don't have that problem, since the transmitter is effectively always on while transmitting. That's why you don't notice that sound very often anymore.
        yaantc 10y ago
        LTE uses OFDMA, which has nothing to do with CDMA (no superposition and coding separation). OFDMA is a combination of frequency and time division: time wise, the allocation unit is a subframe of 1 ms (to be compared with a 2G GSM burst duration of 0.577 ms, so not that far) and frequency wise a subframe is made of "resource blocks" (RBs) of 12 subcarriers of 15 kHz each (so 1 RB = 180 kHz total). What's allocated to a device is a set of RB in a subframe, and this is repeated as needed accross subframes in time. 3G used a 10 ms allocation unit, but with HSPA it's been reduced to 2 ms to become more "TDM-like" (it turns out that in real life code superposition is not so good, better split in time and do less superposition: less interference, less power consumption, better results). I honestly don't know the source of the 2G noise, but from the above it's not as simple as TDM vs. no TDM, as current 3G and LTE both in practice have a time-based allocation component on roughly similar granularity as 2G. One difference could be the transmission power: 2G can go up to 2W, while LTE is 200 mW maximum so 10 times less. I don't have 3G peak Tx power in mind, but in practice I guess it should be closer to LTE than 2G (interference minimization in a same frequency / reuse 1 network: both LTE and CDMA are reuse 1 deployment, while 2G is not). That will certainly cause a 2G device to have higher power spikes. And I guess the details of the transmit pattern are likely to play a role too.
        kuschku 10y ago
        > That's why you don't notice that sound very often anymore. Except yesterday. And today. And every second day in my life. Because even my Nexus 5X in a 4G network occasionally sends/receives SMS in GSM mode.
  - PascLeRasc 10y ago
    Ground is an "implied pole" as you'd need it for anything, it's just 3 different upstream channels (L,R,mic) feeding into it.
- eon1 10y ago
  While in practice that may be mostly true, it's not necessarily a fact. Unbalanced microphones can and do exist.
  - quesera 10y ago
    I think GP was referring to the conductors on a standard stereo+mic 3.5mm plug, which of course really has four conductors, but three prominent dividing marks. These are unbalanced mics. I've never seen balanced mics outside of recording studios.
jrockway 10y ago
Apple headphones work with other devices. I use the iPhone headphones for videoconferences on my Asus Chromebox, for example.

joecool1029 10y ago

Pretty sure Blackberry use the Apple 'standard' as well.

wlesieutre 10y ago

To be more precise than "they don't work because Apple is terrible," the two competing pinout standards are CTIA (previously meaning Cellular Telephone Industries Association) and OMTP (Open Mobile Terminal Platform). According to Wikipedia, the OMTP devices include: * old Nokia (and also Lumia starting from the 2nd gen) * old Samsung (2012 Chromebooks) * old Sony Ericsson (2010 and 2011 Xperias) * Sony (PlayStation Vita) * OnePlus One * Xbox One controller with head phone jack * iPhone sold in China and CTIA devices include: * Apple * HTC * LG * Blackberry * latest Nokia (including 1st gen Lumia as well as later models) * latest Samsung * Jolla * Sony (Dualshock 4) * Microsoft (including Surface and Xbox One controller with chat adapter) * most Android phones https://en.wikipedia.org/wiki/Phone_connector_(audio)#TRRS_standards https://en.wikipedia.org/wiki/Phone_connector_(audio)#TRRS_s... I haven't personally tested most of those, but IIRC when I had a Surface Pro the iPhone TRRS earbuds worked fine with it.

stonogo 10y ago
CTIA is a post-facto 'standardization' of what used to be known as 'AHJ,' which came about once companies needed a name for 'Apple-compatible' without actually naming Apple. CTIA is primarily a lobbying organization, and their past hits include laws that made it easier for the US government to surveil email and an attempt to get the US government to shut off TV broadcasting entirely. OMTP was an actual standard from a real-life standards body -- the same one that brought us micro-USB across all non-Apple phones. We lost functionality when we lost OMTP; imagine a world where you had dedicated buttons for track forward and back. Having been involved in the design phase of devices that supported each standard, I miss OMTP.
- comex 10y ago
  > We lost functionality when we lost OMTP; imagine a world where you had dedicated buttons for track forward and back. There's one argument, albeit small, for killing the headphone jack. USB HID has included track control keycodes since forever, so USB earphones should be able to control playback by appearing as a HID device... I think... Of course, there too Apple is off doing their own thing with Lightning.

jws 10y ago

For the curious or confused by the "when you tap the button it shoots an electrical signal that the phone will pick up and interpret" in the article, the control buttons are implemented as resistors switched across the mic/ground pair. The mic is 1000Ω or higher. The functions resistors are lower. You can see nice diagrams at… http://source.android.com/devices/accessories/headset/plug-headset-spec.html http://source.android.com/devices/accessories/headset/plug-h...

hugodahl 10y ago
Very nice and handy reference! Will give me something to compare against and my Pixel and Amazon headset. Apparently, vol up on the headset triggers the assistant, while all other buttons work as expected. Oddly, the same headset worked flawlessly on a OPO and Nexus 6. And Google hardware support cannot recommend a specific make/model, just one with "an on/off switch for the mic".

tooFastFuckYou 10y ago

The best is when Apple's shitty headphone jack goes bad, the connection gets flaky, and it starts sending spurious "commands" to the phone. And why is Apple's headphone jack shitty? The conspiracy theorist would say that Apple wanted to justify their idiotic decision to eliminate it. The realist would say it's because of Apple's idiotic mania to make everything "thinner," which is used as an excuse to compromise everything from battery life to the quality of internal components on all of its products.

simonjgreen 10y ago

This is not a fair representation of the situation at all, and also doesn't even hold true. For example, I recently switched from iPhone to Galaxy S7. My apple earbuds centre button pauses and resumes but the volume controls do nothing. So the problem is not as straightforward as Apple vs Android.

rickdeckard 10y ago

Apple didn't patent a "resistance", they implemented a control-chip in their headphones starting from the iPod Shuffle in ~2009, and patented that chip. Purpose was to ensure a revenue-share from headphones so that every accessory-maker who wanted in-line controls had to pay a license to Apple to use the control-chip. (the control-chip was meanwhile reverse-engineered and its functionality is now integrated in non-licensed headphones as well)

bostand 10y ago
"ensure a revenue-share" Such a nice word for such an ugly business practice....

tener 10y ago

> In other words- you could have a device with the same TRRS Pinout as apple products- but the headset wont work because the resistances (ohms) of the headphones send signals that your phone is not allowed to interpret into the correct actions (since apple patented these) Can you seriously patent actual resistances?

mattkevan 10y ago

Has this got anything to do with the way inline controls seem to be unreliable in Android? I got out of the habit of using them as there was only a 50/50 chance of anything happening when pressing a button. Sometimes even when successful it would take a while to take effect. Pressing the button a few times in case it didn't register led to nonsense like it stopping and starting rapidly a few seconds later. I first noticed this on a Fairphone on 4.2 and just thought it was due to a sluggish phone on an old system, but the problem remained on a Nexus 6 with versions 5 and 6. Also Android seems to be bad at remembering the last audio app that was open. On iOS, you can listen to something, unplug the headphones, do something, plug them back in, hit the play button and you carry on where you left off. Android not so much - you have to manually open the app for it to work. Although I once had a podcast app and a music app start at the same time.

aembleton 10y ago
I find Poweramp [1] reliably starts every time I plugin my earphones. 1. http://powerampapp.com/ http://powerampapp.com/
hsod 10y ago
> On iOS, you can listen to something, unplug the headphones, do something, plug them back in, hit the play button and you carry on where you left off In my experience, this doesn't work very well anymore on iOS 10

codfrantic 10y ago

To make things even more complicated, I have a Sony Xperia Z2 which uses a 5 point jack plug TRRRS, as far as I know the extra connection is only used to receive microphone signal from the included noise cancelling headphones.[1] (Since the noise cancelling logic is handled on the phone). [1] https://www.sonymobile.com/global-en/products/accessories/digital-noise-cancelling-headset-mdr-nc31em/ https://www.sonymobile.com/global-en/products/accessories/di...

nickcano 10y ago

This causes a ton of compatibility problems, and it's worse that a lot of companies don't seem to care and advertise compatibility anyways. I noticed this a while ago when I wrote this review: https://www.amazon.com/review/R2RH78QWKSM5W7/ref=cm_aya_cmt?ie=UTF8&ASIN=B004SP0WAQ https://www.amazon.com/review/R2RH78QWKSM5W7/ref=cm_aya_cmt?...